Fast activating catalyst

• US 8,183,173 B2
• Filed: 12/21/2007
• Issued: 05/22/2012
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Chevron Phillips Chemical Company LP (Chevron Corp.)
• Original Assignee: Chevron Phillips Chemical Company LP (Chevron Corp.)
• Inventors: McDaniel, Max P., Benham, Elizabeth A., Cymbaluk, Ted, Neil, George
• Primary Examiner(s): Wu, David W
• Assistant Examiner(s): Eng, Elizabeth
• Application Number:
  US11/963,530
• Publication Number:
  US 20090163681A1
• Time in Patent Office: 1,614 Days
• Field of Search: 526/129, 526/72, 526/30, 526/106, 502/233, 502/256
• US Class Current: 502/256
• CPC Class Codes: B01J 21/08 Silica
• CPC Class Codes: B01J 23/26 Chromium
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/638 more than 1.0 ml/g
• CPC Class Codes: B01J 35/647 2-50 nm
• CPC Class Codes: B01J 37/0207 Pretreatment of the support
• CPC Class Codes: B01J 37/036 to form a gel or a cogel
• CPC Class Codes: B01J 37/06 Washing B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: C08F 10/00 Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
• CPC Class Codes: C08F 110/02 Ethene
• CPC Class Codes: C08F 2500/07 High density, i.e. > 0.95 g/cm3
• CPC Class Codes: C08F 2500/09 Long chain branches
• CPC Class Codes: C08F 2500/12 Melt flow index or melt flow ratio
• CPC Class Codes: C08F 2500/17 Viscosity
• CPC Class Codes: C08F 4/025 Metal oxides
• CPC Class Codes: C08F 4/78 selected from chromium, molybdenum or tungsten

Abstract

A method of preparing a catalyst comprising aging a silica support in an alkaline solution to produce an alkaline aged silica support, removing at least a portion of the alkaline solution from the alkaline aged silica support to produce a dried silica support, and activating the silica support to produce a catalyst composition, wherein alkaline aging lowers the surface area of the silica support to less than about 50% of the original value and wherein activation of the silica support is carried out in batches of equal to or greater than about 500 lbs for a time period of less than about 8 hours. A method of preparing a polymer comprising alkaline aging a silica support material, adding chromium to the silica support material prior to the alkaline aging, after the alkaline aging, or both to form a chromium-silica support, rapidly activating the chromium-silica support to produce an activated olefin polymerization catalyst, contacting the activated olefin polymerization catalyst with at least one monomer in a reaction zone under conditions suitable to produce a polymer, and recovering the polymer.

Claims

1. A method of preparing a catalyst comprising:

aging a silica support in an alkaline solution to produce an alkaline aged silica support;

removing at least a portion of the alkaline solution from the alkaline aged silica support to produce a dried silica support; and

activating the silica support to produce a catalyst composition, wherein alkaline aging lowers the surface area of the silica support to less than about 50% of the original value, wherein the silica support has a surface area of less than about 300 m²/g, wherein activation of the silica support is carried out in batches of equal to or greater than about 500 lbs for a time period of less than about 8 hours, and wherein a chromium conversion to chromium (VI) is from about 0.35 wt. % to about 0.65 wt. % based on the total weight of the catalyst when the chromium level is from about 0.2 wt. % to about 2 wt. %.

2. The method of claim 1 wherein the aging is carried out at a temperature of from about 60°

C. to about 90°

C.

3. The method of claim 1 wherein the alkaline solution has a pH of from about 8 to about 13.

4. The method of claim 1 wherein the aging is carried out for a time period of from about 1 to about 24 hours.

5. The method of claim 1 wherein removing at least a portion of the alkaline solution further comprises contacting the alkaline aged support with an organic solvent, thermally drying the alkaline aged support, spray drying the alkaline aged support or combinations thereof.

6. The method of claim 1 wherein commercially activating the alkaline aged composition further comprises heating the composition to a temperature equal to or greater than about 700°

C.

7. The method of claim 1 wherein the silica support further comprises titania.

8. The method of claim 1 further comprising adding chromium to the silica support prior to aging, during aging, after aging, or combinations thereof.

21. The method of claim 1 wherein the catalyst composition has a pore diameter of from about 50 Å

to about 400 Å

.

22. The method of claim 1 wherein the catalyst composition has a pore volume of from about 1 cc/g to about 3 cc/g.

23. The method of claim 1 wherein the activation is carried out for a time period of less than about 1 hour.

25. The method of claim 1, wherein the temperature is ramped at a rate of about 2.5°

F. per minute during activation of the catalyst.

9. A method of preparing a polymer comprising:

alkaline aging a silica support material;

adding chromium to the silica support material prior to the alkaline aging, after the alkaline aging, or both to form a chromium-silica support;

rapidly activating the chromium-silica support to produce an activated olefin polymerization catalyst, wherein the chromium-silica support is rapidly activated in batches of equal to or greater than about 500 pounds, wherein activation of the chromium-silica support occurs in less than about 8 hours, wherein the silica support has a surface area of less than about 300 m²/g;

contacting the activated olefin polymerization catalyst with at least one monomer in a reaction zone under conditions suitable to produce a polymer, and wherein the chromium conversion to chromium (VI) is from about 0.35 wt. % to about 0.65 wt. % based on the total weight of the catalyst when the chromium level is from about 0.2 wt. % to about 2 wt. %; and

recovering the polymer.

10. The method of claim 9 wherein the silica support material is alkaline aged by contact with a solution having a pH of from about 8 to about 13 at a temperature of from about 60°

C. to about 90°

C. for a time period of from about 1 to about 24 hours.

11. The method of claim 9 wherein the silica support further comprises titania.

12. The method of claim 9 wherein alkaline aging lowers the surface area of the silica support to less than about 50% of its original value.

13. The method of claim 9 wherein the polymer comprises polyethylene having a density of greater than about 0.945 g/cc.

14. The method of claim 13 wherein the polymer has a melt index of from about 1 to about 10.

15. The method of claim 14 wherein the polymer has a CY-a value that is less than about 0.2.

16. The method of claim 15 further comprising blow molding the polyethylene.

24. The method of claim 9 wherein the polymer has a die swell of from about 5% to about 50% when compared to an otherwise similar catalyst prepared in the absence an alkaline treatment.

17. A method of preparing a polymer comprising:

alkaline aging a silica support material;

adding chromium to the silica support material prior to the alkaline aging, after the alkaline aging, or both to form a chromium-silica support; and

rapidly activating the chromium-silica support to produce an activated olefin polymerization catalyst, wherein rapidly activating chromium-silica support comprises heating to a temperature of equal to or greater than about 700°

C. for a time period of less than about 8 hours, wherein the chromium-silica support is rapidly activated in batches of equal to or greater than about 500 pounds, wherein the silica support has a surface area of less than about 300 m²/g, and wherein the chromium conversion to chromium (VI) is from about 0.35 wt. % to about 0.65 wt. % based on the total weight of the catalyst when the chromium level is from about 0.2 wt. % to about 2 wt. %.

18. The method of claim 17 wherein the silica support material is alkaline aged by contact with a solution having a pH of from about 8 to about 13 at a temperature of from about 60°

C. to about 90°

C. for a time period of from about 1 to about 24 hours.

19. The method of claim 17 wherein the silica support further comprises titania.

20. The method of claim 17 wherein alkaline aging lowers surface area of the silica support to less than about 50% of its original value.